A replacement gasket for your Duromatic pressure cooker. To find the size of your pressure cooker gasket, don't measure it, instead run your finger around the inside of the gasket until you find the words 'Original Kuhn Rikon', there are 4 digits preceding the text - either 1657, 1501, 1502 or 1719. 1657 - to fit 20cm pressure cooker 1501 - to fit 22cm pressure cooker 1502 - to fit 24cm pressure cooker 1719 - to fit 28cm pressure cooker